I guess you were confused or maybe we weren't clear about what the demo contains , the game page says

"at the moment the demo contains only the prolog.
The prolog is very short and its just so you can get the hang of the game.
the full game contains 7 different rooms with a lot of hard puzzles to solve!."

You can expect extremely hard puzzles in the full game, the demo is simply showing the game idea and how to play kinda thing.

The demo is the prolog of the game, think about it as the "tutorial" :)

the full game is nothing like the prolog, you will need to figure out the answer and not just finding the answer

i can assure you that if you liked the overall idea and what you're missing is a challenge, you will NOT be disappointed .